Flan's Mod: Reloaded loads from Content Packs you can find here on CurseForge, turning simple JSON files, sounds and textures into a lethal upgrade for your world.
This is the official continuation of Flan's Mod, rewritten from the ground up for a new era of Minecraft.
Details and tutorials will be available soon, but in the meantime you can try out a beta version of the Content Tool over on GitHub
Using the Unity Editor environment for content management, you can import old 1.12.2 packs into the Editor, tweak assets in the Unity Inspectors and export directly to a new Flan's Mod: Reloaded format content pack.
As a result of large scale refactoring and a new content system, 1.12.2 and earlier packs do not work in Flan's Mod: Reloaded without being processed by the pack creator or license holder with the new tool.
Make sure you install some content packs as well, Flan's Mod has no default content.
You can also create your own packs. Check out the Flan's Mod Discord for more info coming soon.